Minimum friction contactors

ABSTRACT

A device having a flexible ribbon member with conductive portions, selectively bulged or urged into contact with an adjacent cooperating unit having conductive portions. The location of the contact is controlled by an element or elements capable of translation parallel to the longitudinal axes of the ribbon and cooperating unit.

United States Patent 1 Siegel 51 May 29,1973

[54] MINIMUM FRICTION CONTACTORS [76] Inventor: Henry Siege], 3 Talbot Drive, Lake Success, NY. 11020 [22] Filed: Aug. 6, 1970 [21] Appl. No.: 61,748

[52] U.S. Cl ..200/166 811, 200/16 D, 200/166 BB,

335/205, 338/96 [51] Int. Cl ..H01h l/16, HOlh 36/00 [58] Field of Search ..200/166 BA, 166 BB,

200/61.14,166 BH,166 PC, 83 N, 153 LA, 16 D; 335/205; 338/154, 158, 96; 317/101 F;

[56] References Cited UNITED STATES PATENTS 3,399,282 8/1968 Nagashima et al ..200/16 D X 3,502,824 3/1970 Bonacquisti 2200/16 D 1,683,059 9/1928 Van Deventer ..338/96 3,516,041 6/1970 Estlick ..338/96 X 7/1966 Shlesinger, Jr. ..200/16 X 3,377,604 4/1968 Forrest..... 2,575,230 ll/1951 Mork 3,388,356 6/1968 Myatt, Jr. et al. 2,874,237 2/1959 Shlesinger, Jr. ..200/166 BA FORElGN PATENTS OR APPLICATIONS 470,399 12/1950 Canada ..338/158 Primary Examiner-Herman J. Hohauser Assistant ExaminerRobert A. Vanderhye Attorney-Robert R. Strack and James A. Eisenman [57] ABSTRACT A device having a flexible ribbon member with conductive portions, selectively bulged or urged into contact with an adjacent cooperating unit having conductive portions. The location of the contact is controlled by an element or elements capable of translation parallel to the longitudinal axes of the ribbon and cooperating unit.

14 Claims, 9 Drawing Figures PATENTEU MAY 2 9 I975 SHEET 2 UF 2 INVENTOR. HENRY 8/ E GE L ATTORNEYS MINIL'IUM FRICTION CONTACTORS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to electrical contactors; and more particularly, to electrical switching devices suitable for repetitive operation.

2. Description of the Prior Art The switching of electrical power between various points in a system, or the pick-up of power from a coil or other device, are functions encountered in almost all circuit configurations. The devices for accomplishing these functions include such diverse units as standard knife switches, mercury switches, miltideck rotary switches, potentiometers, voltage regulators, and commutators. One finds the current transferred by such devices to range from microamperes to many amperes.

It has been recognized that the repetifive use of contacting devices results in mechanical wear as well as possible degeneration of the devices due to current flow therethrough. With respect to mechanical wear, one encounters deterioration of bearings and contacting surfaces as a result of friction. In addition, the made-and-break operation of some devices results in pitting and ultimate destruction of the contacting surfaces.

Many remedies and techniques are presently employed in order to minimize the deterioration of switching devices. These techniques include the utilization of special materials, unique structural configurations, and the employment of ancillary circuitry. The efficacy of these various techniques depends upon the particular device and the application involved.

SUMMARY OF THE INVENTION The present invention provides a substantially frictionless contacting arrangement which makes possible the establishment of electrical contact between relatively movable surfaces. The arrangement can be employed in either switching or potentiometric-type applications and lends itself to a wide variety of physical structures.

It is an object of the present invention to provide a substantially frictionless electrical contact arrangement.

1 It is another object of the invention to provide an improved electrical contacting arrangement suitable for use as a switch.

It is another object of the invention to provide an improved electrical contacting arrangement suitable for use in conjunction with variable impedance devices.

It is another object of the invention to provide an improved electrical contacting arrangement adaptable to multiple contact and multiple switching applications.

In accordance with the invention, there is provided a device for establishing substantially non-frictional contact between a stiff resilient ribbon and an adjacent cooperating unit displaced therefrom by a predetermined amount, including means effective to bulge the resilient ribbon into contact with the cooperating unit at any desired position. Both the resilient ribbon and the cooperating unit may be selectively provided with conductive portions to effect a low impedance path therebetween at desired positions.

In one illustrative embodiment, a variable impedance device is provided by selectively contacting the windings on the inner surface of a toroid. A flexible conductive strip is secured within the toroid and a slotted insulating sleeve is interposed therebetween. The circumference of the conductive strip is selected to be greater than that of the confining sleeve and consequently a bulge is developed which extends radially beyond the sleeve and into contact with the inner surface of the toroid.

In another illustrative embodiment, a multi-contact switching device is provided wherein an armature composed of a flexible conductive strip selectively contacts conductive segments circumferentially disposed about the outer periphery of an insulated disc. The flexible strip is circumferenn'ally mounted upon one face of a base disc, and has a length slightly greater than the circumference embraced. Thus, the strip tends to bulge in an axial direction. An insulating disc with a radial aperture is interposed between the disc with the conductive segments and the strip and selectively positions the bulge in contact with the segments.

A more complete appreciation of the objects and features of the present invention will be available following a consideration of the following detailed description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective schematic illustrating the principles involved in developing a structure embodying the invention;

FIG. 2 is a front elevation view of the illustrative structure'shown in FIG. 1;

FIGS. 3A through 3C illustrate several typical contact configurations that may be used in connection with various embodiments of the invention;

FIGS. 4A and 4B are sketches illustrating the principles of the invention from another aspect;

FIG. 5 is an exploded view of a variable resistance constructed in accordance with an illustrative embodiment of the invention; and

FIG. 6 is an exploded view of the multi-contact switch constructed in accordance with another illustrative embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates an electrical contacting system fabricated by placing a flexible ribbon or strip 10 upon a rigid planar base member 11. The ends 12 and 13 of the ribbon are secured to the base member 11 and the ribbon is slightly longer than the substrate. Thus, there is a tendency for the ribbon to bulge. A slide or collar device 15, having an aperture 16 therein, is placed over the ribbon 10 and acts to retain it in close proximity to the base member 11. This retention action is absent at the aperture 16 and consequently a controlled convex bulge 14 is formed. As the collar 15 slides from left to right, as illustrated in FIGS. 1 and 2, the bulge l4-follows the aperture. A cooperating plate 20 is positioned above the base member 11 and substantially parallel to the surface thereof. The normal separation between plate 20 and base member 11 is such that the upper portion of bulge 14 contacts plate 20. For clarity of illustration, FIG. 1 shows a greater separation; but FIG. 2 illustrates the correct relationship.

It will be immediately apparent that as the collar 15 is moved, the contact point formed between bulge 14" and plate 20 will travel. In essence, a line or surface contact is established and this contact is not wiped along the surfaces as it moves; rather, new portions of flexible ribbon form the contact. Because there is no wiping action, there is substantially no frictional wear. Still further, the contact moves without a rapid makeor-break action at any point. v

The versatility of devices embodying the basic structure of the invention may be better appreciated from a consideration of FIGS. 3A through 3C. These figures show conductive segments 24 mounted upon an insulating surface 25. Surface 25 may be either the plate 20 of the device shown in FIGS. 1 and 2, or it may be the ribbon 10 of that device. The conductive segments may be etched, glued, or otherwise bonded to the surface. Since there is minimal frictional wear, it is possible to use thin layers of material and precious metals may be ecomonical.

The layouts in FIGS. 3A through 3C are developed with the assumption that the collar may. travel back and forth from left to right. Assume further that the layouts represent the contact configuration on a plate 20, and that flexible ribbon 10 is a sheet of conductive material.

FIG. 3A then represents a single armature multiple contact switch wherein the various connections are effected as the collar 15 is positioned across the device. The spacing between conductive segments 24 and the width of each segment are selected in accordance with the number of contacts desired, the accuracy of positioning, and the degree of surface contact between the top of bulge 14 and the segments.

FIGS. 33 and 3C suggest the switch programming possibilities inherent with the present inventive design. The transverse arrangement of conductive segments 24 in FIG. 3B, permits establishing connections to a variety of circuits for predetermined time intervals in accordance with the transverse length and width of each segment and the speed of collar travel. The columnar arrangement of segments 24 in FIG. 3C, permits establishing connections with several circuits for the time intervals determined by the length of the segments and the speed of collar travel. The programming possible merely by dimensioning and interconnection of the contact segments is virtually unlimited.

The basic characteristics of ribbon 10 are its flexibility and the ability to retain the bulge with a satisfactory surface contact at its upper portion. Numerous materials are available and will be immediately apparent to those skilled in the art. The strip need not be conductive itself. Conductive materials may be bonded or etched onto its surface.

It should also be appreciated that some applications will benefit from the development of several bulges in ribbon 10 and, in suitable designs, the bulges may project in opposite directions to effect contacts with opposite surfaces of the ribbon.

In other embodiments of the invention, the retaining collar 15 and/or the ribbon 10 may be provided with bearing surfaces which contact along the edges of the ribbon. For example, at the opposite transverse edges of the device shown in FIG. 1, bearing tracks 17 and 18 on ribbon 10 cooperate with the lower surface of collar 15. By utilizing such bearing tracks, it is possible to avoid frictional contact between the collar and the electrical contacting surfaces of the device. On the other hand, one may find it desirable to effect a burnishing of the electrical contacting surface and this can be advantageously eflected by the lower surface of the collar 15.

The utilization of an elongated flexible ribbon as one element of a contacting pair, can also lead to structures which do not employ a restraining collar. FIGS. 4A and 43 provide an example of such a structure, wherein a stifi resilient ribbon is mounted between fixed point 101 and 102 in proximity to a cooperating unit 120, comprising a substrate 121 and coil 122. Ribbon 100 is normally biased away from unit 120; but its resilience renders it susceptible to temporary deformation in order to establish the desired contact.

Numerous activators are available for bringing ribbon 100 into contact with the cooperating unit 120. The particular activator used depends upon the results desired and the means available. As one example, a jet or jets of air might be used if the source were disposed above the ribbon 100 remote from the unit 120. As another example, a vacuum arrangement below unit 120 might be used. FIG. 4B illustrates a third example, wherein a magnet 115 is used. Obviously, when a magnet is employed, it is necessary that ribbon 100, or at least some constituent part thereof, be of magnetic material.

As shown in FIG. 4B, ribbon 100 is deformed in a sinusoidal manner producing convex portions 104, 105 and a contacting concave portion 103. Movement of magnet alongan axis substantially parallel to the longitudinal axis of elements 100, will result in a corresponding movement of concave portion 103. If the strength of the magnetic field is increased, there will be a tendency to flatten a greater part of portion 103 into contact with unit 120. As illustrated in the other embodiments of the invention, an apertured member 123 may be introduced to control the dimensions and position of the bulge.

It is important to note that by using a non-contacting actuator such as magnet 115, it becomes possible to place the contacting elements themselves into an isolated environment. For example, elements 100 and 120 may be hermetically sealed. Obviously, magnet 115 may be an electromagnet and need not be disposed exactly as shown. The primary consideration lies in establishing the necessary flux linkage to effect contact of the ribbon 100 and coil 122. The preceding and following discussion concerning contact configurations and structural forms will also suggest modifications that may be made advantageously.

To utilize the principles of the present invention in convenient sn'uctures of one form, it has been found desirable to form the base member 11 of FIGS. 1 and 2 in a closed, or reentrant, loop. When this is done, collar 15 can be rotated about the axis of the loop and the bulge of ribbon 10 will project radially to contact a cooperative member 20 either surrounding or encircled by base member 11. Such devices are quite compact and in appearance are similar to conventional switching and control devices.

FIG. 5 illustrates a rheostat wherein a resistive element 30 is prepared in the form of toroidal coil having bare wires. The toroid is arranged for mounting about a shaft 23 upon and about which the other elements of the invention are also mounted. At the rear of the FIG- URE, there is a casing or housing 26, and a base member 27 having an axially projecting shoulder 28 thereon. The base member 27 is secured to the housing 26. Adapted to fit over the shoulder 28 is a flexible conductive ribbon 29. During assembly, the ribbon 29 may be secured against rotation relative to coil 30. In other applications, this may not be necessary. A sleeve or ring 31 is securedly mounted to shaft 23 via a bar and bearing assembly 33, 34. Ring 31 is adapted to encircle shoulder 28, sandwiching ribbon 29 therebetween. Aperture 32 permits the excess length of ribbon 29 to extend as a radial bulge 35 which contacts the inner surface of toroid 30.

When the elements illustrated in FIG. 5 are telescoped together, with the torodoil coil 30 and the base member 27 non-rotatably mounted within housing 26, rotation of shaft 23 effects a rotation of the apertured ring 31 and the bulge 35 will be rotationally positioned in accordance with the position of the aperture. The dimensions of the toroidal coil 30 and ribbon 29 can be selected to establish either line contact or surface contact between bulge 35 and the inner surface of coil 30. By suitable connection of electrical conductors to ribbon 29 and coil 30, either a potentiometer or a variable resistance device is provided.

As explained hereinabove, numerous modifications may be made in the specific elements of FIG. 5, in order to produce devices performing particular functions. Thus, the toroidal core 30 may be replaced by a cylindrical unit having a plurality of conductive segments axially and/or circumferentially aligned thereabout. In this respect, the device may serve either as a commutator or as a switch. In addition, ribbon 29 may be provided with circumferentially extending conductive strips, which are disposed to effect desired switching actions as the shaft 23 is rotated.

The invention may also be incorporated into devices of disc-like form as shown, for example, in FIG. 6. This form is particularly advantageous when the ultimate device is to function as a multi-deck switch. The embodiment in FIG. 6 comprises a first planar disc 40 having a plurality of radially extending conductive segments 41 disposed in a ring at the outer edge thereof. For ease of illustration, element 40 may be considered to be formed of av transparent insulating disc 42 and opaque conductive segments 41 secured thereon. The segments 41 are disposed on the surface of element 40 which faces the housing. This planar disc element 40 is mounted by a suitable bearing (not shown) upon a shaft 43 and is adapted to be non-rotatably secured to a housing 50. The base member of this device appears as insulated disc 43 adjacent to housing 50 and is adapted to be affixed therein. Flexible ribbon 44 may be secured against rotation by a pin 49 which projects from disc 43 through hole 45, or by other suitable means. Retaining disc 46, having aperture 47, is mounted on shaft 43 in proximity to and between elements 40 and 44. Since ribbon 44 is longer than the circumference of the ring it forms, it forms bulge 48 for contacting with element 40. The position of bulge 48 is determined by the angular position of disc 46 which is the only element connected to shaft 43.

As was explained relative to the other embodiments of the invention, modifications in the basic elements presented in FIG. 6 will be immediately apparent to those skilled in the art. These modifications will be of particular value depending upon the function the device is to serve. It is immediately apparent that the multiple contact disc 40 may be replaced by toroidal cores such as that shown in FIG. 5. In this case, bulge 48 would project and place itself into bearing contact with the edge of such a coil. In addition, plural apertures may be provided in element 44 and the conductive portions of the flexible ribbon may be selectively positioned in accordance with any predetermined scheme.

A number of specific embodiments of the invention have been described and typical modifications of these embodiments have been suggested. It is understood that those skilled in the art will be able to apply the teachings of the invention in a variety of ways. All such modifications and the resulting devices which fall within the spirit and teachings of the invention are intended to be covered by the following claims.

What is claimed is;

1. A low friction contacting device comprising a first member disposed in a predetermined position, a stiff resilient member disposed adjacent to said first member, an apertured member disposed between said first member and said resilient member and having at least one aperture therein, said resilient member being restrained from contact with said first member, except through said aperture, and means for urging said resilient member into contact with said first member, said means being disposed on the remote side of said first member.

2. A low friction contacting device as defined in claim 1, wherein said resilient member is magnetic and wherein said last mentioned means creates a magnetic field.

3. A low friction contacting device as defined in claim 1, wherein said resilient member is biased to a position away from said first member.

4. A low friction contacting device comprising a first member disposed in a predetermined position, a stiff resilient member disposed adjacent to said first member, an apertured member disposed between said first member and said resilient member and having at least one aperture therein, said resilient member being restrained from contactwith said first member, except through said aperture, and means for urging said resilient member into contact with said first member, wherein said resilient member and said first member lie along substantially parallel longitudinal axes, and wherein said means for urging said resilient member translates along an axis substantially parallel thereto.

5. A low friction contacting device comprising a base member having a flat insulating surface, a flexible member having conductive portions secured to said base member to effect a projecting bulge from the surface of said base member, a contacting member having conductive portions located adjacent to said flexible member and in contact with said projecting bulge, and an apertured member between said flexible member and said contacting member confining said bulge to de: sired positions, said apertured member being movable relative to said other members.

6. A low friction contacting device as defined in claim 5, wherein said flexible member is supported between points that are closer than the length thereof.

7. A low friction contacting device as defined in claim 5, wherein said flexible member and said contacting member have substantially flat faces opposing one another.

8. A low friction contacting device as defined in claim 5, wherein said base member has a shorter effective length than said flexible member.

9. A low friction contacting device as defined in claim 8, wherein said apertured member has a shorter effective length than said flexible member.

10. A low friction contacting device as defined in claim 5, wherein said apertured member is movable relative to said contacting member only.

11. A low friction contacting device as defined in claim 5, wherein said contacting member comprises a coil.

12. A low friction contacting device as defined in claim 5, wherein said contacting member comprises a plurality of contacts.

13. A low friction contacting device as defined in claim 5, wherein said base member, said flexible member, said apetured member, and said contacting member, are formed in a closed loop, are coaxially mounted, and are surrounded by the succeeding members, respectively; said apertured member being rotatable relative to the other members.

14. A low friction contacting device as defined in claim 5, wherein said base member is formed as a planar disc, said flexible member is formed as a ring adjacent to one surface of said base member, said apertured member is formed as a disc adjacent to said flexible member and has an aperture in the radial region occupied by said ring, and said contacting member is formed as a disc adjacent to said apertured member; said apertured member being rotatable relative to the other members; and all of said members being coaxially mounted. 

1. A low friction contacting device comprising a first member disposed in a predetermined position, a stiff resilient member disposed adjacent to said first member, an apertured member disposed between said first member and said resilient member and having at least one aperture therein, said resilient member being restrained from contact with said first member, except through said aperture, and means for urging said resilient member into contact with said first member, said means being disposed on the remote side of said first member.
 2. A low friction contacting device as defined in claim 1, wherein said resilient member is magnetic and wherein said last mentioned means creates a magnetic field.
 3. A low friction contacting device as defined in claim 1, wherein said resilient member is biased to a position away from said first member.
 4. A low friction contacting device comprising a first member disposed in a predetermined position, a stiff resilient member disposed adjacent to said first member, an apertured member disposed between said first member and said resilient member and having at least one aperture therein, said resilient member being restrained from contact with said first member, except through said aperture, and means for urging said resilIent member into contact with said first member, wherein said resilient member and said first member lie along substantially parallel longitudinal axes, and wherein said means for urging said resilient member translates along an axis substantially parallel thereto.
 5. A low friction contacting device comprising a base member having a flat insulating surface, a flexible member having conductive portions secured to said base member to effect a projecting bulge from the surface of said base member, a contacting member having conductive portions located adjacent to said flexible member and in contact with said projecting bulge, and an apertured member between said flexible member and said contacting member confining said bulge to desired positions, said apertured member being movable relative to said other members.
 6. A low friction contacting device as defined in claim 5, wherein said flexible member is supported between points that are closer than the length thereof.
 7. A low friction contacting device as defined in claim 5, wherein said flexible member and said contacting member have substantially flat faces opposing one another.
 8. A low friction contacting device as defined in claim 5, wherein said base member has a shorter effective length than said flexible member.
 9. A low friction contacting device as defined in claim 8, wherein said apertured member has a shorter effective length than said flexible member.
 10. A low friction contacting device as defined in claim 5, wherein said apertured member is movable relative to said contacting member only.
 11. A low friction contacting device as defined in claim 5, wherein said contacting member comprises a coil.
 12. A low friction contacting device as defined in claim 5, wherein said contacting member comprises a plurality of contacts.
 13. A low friction contacting device as defined in claim 5, wherein said base member, said flexible member, said apetured member, and said contacting member, are formed in a closed loop, are coaxially mounted, and are surrounded by the succeeding members, respectively; said apertured member being rotatable relative to the other members.
 14. A low friction contacting device as defined in claim 5, wherein said base member is formed as a planar disc, said flexible member is formed as a ring adjacent to one surface of said base member, said apertured member is formed as a disc adjacent to said flexible member and has an aperture in the radial region occupied by said ring, and said contacting member is formed as a disc adjacent to said apertured member; said apertured member being rotatable relative to the other members; and all of said members being coaxially mounted. 